Arabidopsis CBP1 Is a Novel Regulator of Transcription Initiation in Central Cell-Mediated Pollen Tube Guidance
Arabidopsis CBP1 Is a Novel Regulator of Transcription Initiation in Central Cell-Mediated Pollen Tube Guidance
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拟南芥 CBP1 是中央细胞介导的花粉管引导中转录起始的新型调节因子。
DOI：
10.1105/tpc.15.00370
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发表时间：
2015-10-01
期刊：
影响因子：
11.6
通讯作者：
Yang, Wei-Cai
中科院分区：
文献类型：
--
作者：
Li, Hong-Ju;Zhu, Shan-Shan;Yang, Wei-Cai
在开花植物中，精子细胞通过雌性信号引导的花粉管输送到胚囊。配子细胞和助细胞都有助于花粉管的吸引。助细胞分泌肽信号来引诱管，而配子细胞的作用尚不清楚。此前，我们发现中央细胞引导（CCG）对于拟南芥花粉管吸引至关重要，但其分子机制尚不清楚。在这里，我们鉴定了 CCG 结合蛋白 1 (CBP1)，并证明它与 CCG、介体亚基、RNA 聚合酶 II (Pol II) 和中央细胞特异性 AGAMOUS 样转录因子相互作用。此外，CCG 作为 TFIIB 样转录因子与 TATA-box 结合蛋白 1 和 Pol II 相互作用。 CBP1 敲低的胚珠在花粉管吸引方面存在缺陷。表达谱显示，ccg 胚珠中富含半胱氨酸的肽 (CRP) 转录物下调。 CCG 和 CBP1 共同调节中央细胞和助剂中的 CRP 子集，包括引诱剂 LURE1。 CBP1 在多种营养组织中广泛表达，特别是在生殖生长的中央细胞中。我们提出 CBP1 通过与 CCG 和介体复合物相互作用，连接转录因子和 Pol II 机制来调节花粉管吸引力。
In flowering plants, sperm cells are delivered to the embryo sac by a pollen tube guided by female signals. Both the gametic and synergid cells contribute to pollen tube attraction. Synergids secrete peptide signals that lure the tube, while the role of the gametic cells is unknown. Previously, we showed that CENTRAL CELL GUIDANCE (CCG) is essential for pollen tube attraction in Arabidopsis thaliana, but the molecular mechanism is unclear. Here, we identified CCG BINDING PROTEIN1 (CBP1) and demonstrated that it interacts with CCG, Mediator subunits, RNA polymerase II (Pol II), and central cell-specific AGAMOUS-like transcription factors. In addition, CCG interacts with TATA-box Binding Protein 1 and Pol II as a TFIIB-like transcription factor. CBP1-knockdown ovules are defective in pollen tube attraction. Expression profiling revealed that cysteine-rich peptide (CRP) transcripts were downregulated in ccg ovules. CCG and CBP1 coregulate a subset of CRPs in the central cell and the synergids, including the attractant LURE1. CBP1 is extensively expressed in multiple vegetative tissues and specifically in the central cell in reproductive growth. We propose that CBP1, via interaction with CCG and the Mediator complex, connects transcription factors and the Pol II machinery to regulate pollen tube attraction.